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arXiv · 1807.02796

Causality and dissipation in relativistic polarizeable fluids

David Montenegro·Giorgio Torrieri
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Abstract

We analyze the breakdown of causality for the perfect fluid limit in a medium with polarizeability. We show that to restore causality a relaxation term linking vorticity and polarization, analogous to the Israel-Stewart term linking viscous forces and gradients,is required. This term provides a minimum amount of dissipation a locally thermalized relativistic medium with polarizeability must have, independently of its underlying degrees of freedom. For ferromagnetic materials an infrared acausal mode remains, which we interpret as a Banks-Casher mode signaling spontaneous magnetization. With these ingredients, we propose a candidate for a fully causal Lagrangian of a relativistic polarizeable system near the perfect fluid limit.

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David Montenegro, Giorgio Torrieri. 2019-08-28. Causality and dissipation in relativistic polarizeable fluids. https://doi.org/10.1103/physrevd.100.056011

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